Ice piece formation and harvesting in refrigeration appliances involves significant energy usage relative to the energy usage of other appliance components, such as interior lighting, compressor operation, etc. Formation of ice pieces in ice trays from water in a liquid phase often involves thermally inefficient processes, e.g., convection. Water is introduced into the tray, and then the water is cooled below the freezing point within the ice making compartment by convective processes. Under most, non-conductive conditions, these freezing processes are slow and can require significant energy usage.
Similarly, release of ice pieces from the tray consumes significant energy. For appliances with automatic ice makers, the appliance must overcome the adhesion forces between the ice piece and the tray to harvest the ice pieces once formed. Mechanical approaches are often successful in grossly removing the pieces (e.g., twisting), but frequently the ice piece quality suffers from ice piece fractures away from the ice piece/tray interfaces. One energy-intensive approach for releasing ice pieces from trays with clean, fractureless surfaces is to locally impart energy in the form of heat to the tray/ice piece interface. Although this approach is usually successful in producing good quality ice pieces, it relies on high energy usage—i.e., electrical energy to drive resistive heating elements. Further, the heat and mechanical movement associated with these approaches may also cause cracking or even fracturing of the ice pieces.